Tooth for digging equipment used in compacted soil



Dec. 28, 1965 w. M. TROEPPL 3,225,467

TOOTH FOR DIGGING EQUIPMENT USED IN COMPACTED SOIL Filed July 15, 1963 INVENTOR. F 6 4 MHMMMTIWPPA BY gag f 7 lrraavi) United States Patent 3,225,467 TOOTH FOR DIGGING EQUIPMENT USED IN COMPACTED SOIL William M. Troeppl, Santa Clara, Calif, assignor, by

direct and mesne assignments, of one-half to Gerald A. Petersen, Santa Clara, Calif., and one-half to Anita E. Petersen, Saratoga, Calif.

Filed July 15, 1963, Ser. No. 294,994

The portion of the term of the patent subsequent to June 19, 1981, has been disclaimed 3 Claims. (Cl. 37142) This invention relates to a new and improved tooth for digging equipment used in compacted soil. Reference is made to copending application Serial No. 203,492, filed June 19, 1962, now Patent No. 3,136,077, of Which the present application is a continuation-in-part. The present invention has particular application to replaceable teeth used in earth-digging equipment such as earth angers, trenching machines and a wide variety of other digging tools.

conventionally, replaceable earth-digging teeth are secured to a toothholder or shank which is attached to the digging equipment or the teeth are attached directly to the digging equipment itself. The present invention employs one widely used conventional type of attachment means for such teeth. The present invention is directed to a tooth having a particular shape in the distal portion which adapts the tooth to digging in caliche, hardpan, sandstone, and rock or similar strata under severe operating conditions. The forward portion of the bottom of the tooth slices into compacted soil and the top surface of the tooth fractures the soil thus sliced. The shape of the distal portion of the tooth cooperates with the shape of the proximal portion thereof to insure effective retention of the tooth on its shank or other holder.

The shape of the distal portion of the tooth is such that the compacted hard, brittle soil or rock structure is broken away in an explosive action by reason of the tapered shape of the tooth and the central ridge or spine on the top and the angularly disposed and curved top surfaces hereinafter described. Accordingly, the tooth may be used to dig through strata not heretofore capable of excavation by equipment of the type heretofore described by conventional teeth.

A particular use for the invention is in the excavation for holes for telephone and other utility poles and in the digging of trenches for cables, conduits and pipes as commonly used in the utility industries. The present invention enables the equipment conventionally used in dirt and clay soils to be used in areas such as Arizona, Las Vegas, Nevada, San Diego and East Sacramento,

California, and the like where hard structure known as' caliche, hardpan, sandstone and rock are encountered and where heretofore the teeth of conventional equipment have failed to perform satisfactorily. Other soil strata which are highly compacted can be excavated.

Essentially the action of the tooth is a penetration of the soil and a rapid and violent movement of the dirt away from the tooth. This action has been referred to above as explosive as contrasted with the less violent, shearing action of conventional teeth of digging clay and dirt.

Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings in which similar characters of reference represent corresponding parts in each of the several views.

In the drawings:

FIG. 1 is a top plan view of a tooth in accordance with this invention.

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FIG. 2 is a front elevation thereof.

FIG. 4 is a longitudinal, vertical sectional view taken substantially along the line 44 of FIG. 1 but showing the tooth in a normal position of use in a conventional earth auger.

FIG. 5 is a transverse sectional view taken substantially along the line 55 of FIG. 4.

The proximal portion of the tooth shown in the accompanying drawings is similar to that shown in Patent No. 2,124,230 and known commercially as the H and L tooth. Such a tooth has on its top surface a longitudinally extending, thick, hard, tough blade or base 11 which extends the entire length of the tooth and is generally rectangular in transverse cross-section. Depending from the rearward two-thirds of blade 11 is a cap 12 having substantially triangular sides 13 and an interconnecting bottom 14. Bottom 14 and the underside of blade 11 converge distally. The upper edges of sides 13 are welded or otherwise secured by means of welds 16 to the undersurface of blade 11. This construction provides a forwardly tapering socket 17 defined by the underside of blade 11, sides 13 and bottom 14. Although blade 11 is hard and tough, the sides 13 are somewhat thinner and more malleable so that they may be deformed to hold the tooth on its holder as hereinafter explained.

As has previously been set forth, the tooth of the present invention may be attached to an earth auger such as that shown in Petersen Patent No. 2,968,880, to a trenching machine, or to a dipper bucket, and to various other equipment used in earth-digging and boring. The details of construction of such equipment and of the attachment of the tooth holder or shank thereto form no part of the present invention and are not herein illustrated or described in detail. However, it should be emphasized that the conditions of operation of such equipment produce severe stresses on the tooth and likewise upon the means of attachment of the tooth to its shank or holder. As shown in FIGS. 4 and 5, a conventional shank 21 partially illustrated herein and which is attached at the righthand end as viewed in FIG. 4 to equipment of the type heretofore described has a top surface 22 which fits against the underside of blade 11, a tapered bottom surface 23 which fits against the top of tooth bottom 14 and straight perpendicular sides 24 Which fit inside sides 13 of the tooth. Thus the forward end or point of shank or holder 21 is complementary to the socket 17 of the tooth. One means of attachment of the tooth to its holder is herein illustrated. There are provided on either side surface 24 spheroidal depressions or dimples 26 located at about the juncture of the rear edges 27 of sides 13 with point 21. As initially manufactured, sides 13 are planar. However, when it is desired to attach the tooth to its holder, a ball peen hammer or similar instrument is used to deform the sides 13 overlying depressions 26 in complementary depressions 28. Such depressions 28 are relatively easily formed by reason of the malleable material of which the sides 13 are fabricated. The cooperative depressions 26 and 28 lock the tooth on its holder against unintentional displacement. Various tools may be provided to remove the tooth from its holder when replacement is necessary.

The distal portion of the tooth has distal side edges 31 which are essentially vertical and in plan view as viewed in FIG. 1 extend forwardly from the side edges 32 of the blade 11 in an ogee curve. At the forward ends of curved edges 31 the curvature is so flat that at reference numeral 33 it is substantially parallel to side edges 32. At the front end of the blade 11 the width between edges 33 is only about one-third the distance 3 between edges 32. The front end 34 of the tooth as viewed in plan is vertical and transverse to edges 32.

Extending down the center of the top of the forward half of the top of the tooth is spine 36. Spine 36 slopes up from the rear of said forward half at about a 45 angle to a peak 37 about one-fourth the distance forward of the proximal end of the tooth and then slopes downwardly-forwardly at a 30 angle toward the front end. The thickness of the tooth at peak 37 is about twice that of blade 11 at the rearward end thereof and at the forward end 34 about one-half that at the rearward portion of blade 11. The juncture 38 between the front end of spine 36 and end 34 is beveled in a triangular wrface 38. The flanks 39 of the spine are curved in arcuate surfaces of relatively large radius. Rearwardly of spine 36, surfaces 41 of the tooth are blended to smoothly fill out the transition from the flat top of blade 11 to peak 37.

The bottom surface of the distal portion is almost flat, but has a slight concavity of maximum extent indicated by reference numeral 42. This shape augments penetration of the soil or rock.

In use in an earth auger, the end 34 of the tooth penetrates or slices the stratum of soil or rock and the spine 36 rather violently fragments the compacted brittle soil in a manner resembling an explosion. Such action is particularly effective in digging holes by means of an earth auger of type shown in Petersen Patent No. 2,578,- 014.

In using the tooth in a trenching machine, the two curved flanks 39 cooperate to cut into the stratum and the narrow front end 34 of the tooth penetrates into the rock or soil.

What is claimed is:

1. In a replaceable earth digging tooth for penetration and explosive-like excavation of brittle, compacted soils having a distal portion and a proximal portion, said proximal portion having substantially parallel side edges,

said distal portion having a blade rectangular in crosssection and substantially more narrow in plan than said proximal portion, the top surface of said blade formed with a substantially straight, longitudinally extending spine sloping downwardly-forwardly, the

flanks of said top surface of said blade on either side of said spine being concave, the front end of said tooth being truncated and square, the side edges of the distal portion of said blade being substantially vertical and in plan being shaped, with forward edges parallel to each other and to said parallel side edges of said proximal portion and smoothly inwardly curved edges interconnecting said side edges of said proximal portion and said side edges of said distal portion, the bottom surface of said distal portion of said blade being generally fiat for cooperation with front end for slicing into the soil, said flanks being shaped to break away soil sliced by said end and bottom surfaces, said proximal portion having a top body comprising an integral rearward extension of said distal portion of said blade, and a socket-forming housing having triangular sides perpendicular to and on the underside of said blade and a sloping bottom interconnecting the lower edges of said sides and tapering distally toward said blade, said sides being deformable, said sides of said socket forming portion being slightly narrower than said side edges of said proximal portion.

2. A tooth according to claim 1, in which the top front corner of said tooth is bevelled.

3. A tooth according to claim 1, in which the bottom of said distal portion is formed slightly concave.

References Cited by the Examiner UNITED STATES PATENTS D. 194,508 2/1963 Cain 37l42 X 309,553 12/1884 Manning 37l42 1,399,337 12/1921 Downie 37--l42 1,927,818 8/1932 Brodersen 37l42 2,124,230 7/1938 Hosmer et al. 37l42 3,136,077 6/1964 Troeppl 37l42 FOREIGN PATENTS 428,327 5/1935 Great Britain.

BENJAMIN HERSH, Primary Examiner. 

1. IN A REPLACEABLE EARTH DIGGING TOOTH FOR PENETRTATION AND EXPLOSIVE-LIKE EXCAVATION OF BRITTLE, COMPACTED SOILS HAVING A DISTAL PORTION AND A PROXIMAL PORTION, SAID PROXIMAL PORTION HAVING SUBSTANTIALLY PARALLEL SIDE EDGES, SAID DISTAL PORTION HAVING A BLADE RECTANGULAR IN CROSSSECTION AND SUBSTANTIALLY MORE NARROW IN PLAN THAN SAID PROXIMAL PORTION, THE TOP SURFACE OF SAID BLADE FORMED WITH A SUBSTANTIALLY STRAIGHT, LONGITUDINALLY EXTENDING SPINE SLOPING DOWNWARDLY-FORWARDLY, THE FLANKS OF SAID TOP SURFACE OF SAID BLADE ON EITHER SIDE OF SAID SPINE BEING CONCAVE, THE FRONT END OF SAID TOOTH BEING TRUNCATED AND SQUARE, THE SIDE EDGES OF THE DISTAL PORTION OF SAID BLADE BEING SUBSTANTIALLY VERTICAL AND IN PLAN BEING SHAPED, WITH FORWARD EDGES PARALLEL TO EACH OTHER AND TO SAID PARALLEL SIDE EDGES OF SAID PROXIMAL PORTION AND SMOOTHLY INWARDLY CURVED EDGES INTERCONNECTING SAID SIDE EDGES OF SAID PROXIMAL PORTION AND SAID SIDE EDGES OF SAID DISTAL PORTION, THE BOTTOM SURFACE OF SAID DISTAL PORTION OF SAID BLADE BEING GENERALLY FLAT FOR COOPERATION WITH FRONT END FOR SLICING INTO THE SOIL, SAID FLANKS BEING SHAPED TO BREAK AWAY SOIL SLICED BY SAID END AND BOTTOM SURFACE, SAID PROXIMAL PORTION HAVING A TOP BODY COMPRISING AN INTEGRAL REARWARD EXTENSION OF SAID DISTAL PORTION OF SAID BLADE, AND A SOCKET-FORMING HOUSING HAVING TRIANGULAR SIDES PERPENDICULAR TO AND ON THE UNDERSIDE OF SAID BLADE AND A SLOPING BOTTOM INTERCONNECTING THE LOWER EDGES OF SAID SIDES AND TAPERING DISTALLY TOWARD SAID BLADE, SAID SIDES BEING DEFORMABLE, SAID SIDES OF SAID SOCKET FORMING PORTION BEING SLIGHTLY NARROWER THAN SAID SIDE EDGES OF SAID PROXIMAL PORTION. 